TRNase activity

Some colicins, such as colicin 5, exhibit tRNase activity as their cytotoxic activity to kill the cell they target. This activity is aimed at the anticodon loops of the tRNA molecule, preventing the tRNA from being recognised in the ribosome. This then prevents the cell from producing proteins, and eventually leads to the death of the cell. This is able to occur with just a single colicin molecule in the cell, following first order kinetics.

tRNase colicins
Colicin E5 Colicin D